IT here is also a priviledged sector, in that it's in most cases an employee's market - few people in IT have their job or the wages at risk, layoffs are rare, etc.
There are some unions for IT personnel, but they aren't very popular or well-known.
There's also the mandatory employee representation (called the Ondernemingsraad in Dutch); every company over 50 employees is required to have one of those. But again, this is rare in IT companies. In part because a few companies I've worked for, IT providers / consultancies, use the 'cell division' tactic (https://nl.wikipedia.org/wiki/Celfilosofie), where a company is divided up into smaller cells of at most 50 people, either by geographic location or specialism, each operating as their own company (on paper).
On the surface this is clever because it means the colleagues will be able to know everyone, or a department is specialized, or a company's finances is more secure. But underneath, it means no cell will ever become large enough to require employee representation. On the surface there is no need because everyone is paid and treated well, but at the same time, another one of these was sold to investors and has shifted course, buying up companies across europe now. I think employees would like to have a say in that, but that's not good for the owners / shareholders.